'Lead free' solder

[Will Stilltry]

Hi all
I know the topic of solder has been covered many times, but has anyone ever tested their 'lead free' solder?
I recently repaired a solder joint but was later concerned that I had inadvertently used the wrong solder, as I had both types on my workbench. To put my mind at ease, I purchased a lead test kit from 'Fleabay' which consisted of swabs, similar to cotton buds. You simply wet the tip of the swab and rub on the area or item that you want to test and if the swab turns red, it indicates the presence of lead. I decided to try one out on a joint that I knew for certain was made using 'lead free' solder and was horrified to see it turn red.
I then tried the swabs on various other joints and on the two different rolls of 'lead free' solder that I had purchased specifically for my build - all indicated lead. I am really at a loss to know what to do now, as I have invested considerable amounts of time and money on the project and cannot face the prospect of starting again.
Does anyone know if there are different grades of lead free solder, the same as there are different grades of lead free brass?
I wonder how many others there are who, like me, researched and took notice of all the information about using safe materials but are now running their stills completely unaware that the 'lead free' solder they have used is not quite what it says on the tin.

Will